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Specialists in Tunnel Water Reuse

How treated tunnelling water is recycled for TBM slurry make-up, dust suppression and concrete batching. It is here because reusing site water cuts both mains demand and the volume that has to be treated for discharge. Treated water is matched to the quality each end-use actually needs — slurry make-up, dust suppression and concrete batching tolerate different residual solids and salinity. Closing the loop in this way reduces both the mains water drawn onto site and the effluent volume that must be treated to consent before discharge, lowering cost and environmental footprint together.

Reuse Opportunities

Turn tunnel and metro dewatering into a valuable water resource for construction operations.

Dust Suppression

Treated dewatering water with TSS below 50 mg/L is ideal for haul road spraying and demolition dust control. Eliminates freshwater purchase for this high-volume non-potable application.

Concrete Production

Water treated to potable-equivalent quality (TSS <10, pH 6.5-8.5, chlorides <500 mg/L) meets BS EN 1008 for concrete mixing. Reduces reliance on municipal supply for batch plants.

Equipment Washdown

TBM cutterhead wash, truck wheel cleaning, and tool washdown use significant water volumes. Recycled dewatering water with oil removal and solids separation meets these needs efficiently.

Soil Compaction

Water for subgrade and backfill compaction requires minimal treatment. Direct use of clarified dewatering water after basic solids removal avoids unnecessary polishing costs.

Landscaping & Irrigation

Tertiary-treated water with nutrient removal is suitable for site revegetation and landscaping. Supports green corridor commitments and biodiversity offset programmes.

Fire Suppression

Treated water stored in fire tanks meets hydrant system requirements. Dual-purpose storage reduces both freshwater demand and emergency supply vulnerability on remote sites.

Treatment for Reuse

Application-specific treatment trains from basic solids removal to potable-equivalent quality.

Basic Solids Removal

Coarse and fine screening followed by lamella clarification or DAF produces water with TSS below 50 mg/L. Suitable for dust suppression, compaction, and washdown applications with minimal chemical addition.

Oil & Grease Removal

TBM hydraulic oils, lubricants, and fuel residues are removed by CPI separators and DAF. Effluent oil content below 5 mg/L protects downstream biological treatment and meets concrete production standards.

Biological Polishing

MBBR or SBR biological treatment removes dissolved organics and nutrients to levels suitable for irrigation and landscaping. Compact footprint fits within limited construction site space.

UV Disinfection

UV-C disinfection achieves 4-log pathogen reduction for water used in worker amenities, concrete production, and sensitive environmental discharge. Chemical-free with no residual formation.

pH Correction

Automated acid or alkali dosing maintains pH within the 6.5-8.5 range required for concrete, irrigation, and discharge compliance. Inline probe control with alarm management.

Quality Monitoring

Online turbidity, pH, and flow instruments with data logging provide continuous evidence of reuse water quality. Automated diversion to discharge protects downstream applications from off-spec water.

Economic & Environmental Benefits

Water reuse delivers measurable financial returns and sustainability credentials.

Freshwater Efficiency Gains

Metro construction projects consume 50,000-500,000 m³ of freshwater over their duration. Reuse can displace 40-70% of this demand, reduction per m³ in water purchase and infrastructure charges.

Discharge Fee Reduction

Every cubic metre not discharged to sewer avoids trade effluent charges of For a project generating 200,000 m³ of dewatering water, this represents benefits

Haulage Cost Avoidance

Water that cannot be reused must be tankered off-site at per m³. On-site treatment and reuse eliminates this cost entirely while reducing road traffic and carbon emissions.

Carbon Footprint Reduction

Reusing water on-site eliminates pumping, tankering, and municipal treatment emissions. Typical projects achieve 200-800 tonnes CO2 benefits over the construction programme.

Sustainability Credentials

Water reuse supports BREEAM, CEEQUAL, and LEED scoring. Demonstrates environmental leadership to clients, regulators, and communities — increasingly important for winning public contracts.

Drought Resilience

Independent water supply insulates construction progress from municipal supply restrictions during drought events. Continuity of concrete production and dust suppression is maintained regardless of external conditions.

Related Pages

Metro & Tunnelling Water Treatment

Metro construction, tunnel boring machines (TBM), and cut-and-cover excavation generate slurry water containing bentonite, cement fines, groundwater contaminants, and tunnelling additives. Treatment systems must handle high solids loading, variable flow rates, and tight site constraints while enabling water recycling to reduce freshwater consumption and tanker discharge volumes.

TBM Slurry Treatment

Desanding and desilting plants separate spoil from bentonite slurry for EPB and slurry TBMs.

Cut-and-Cover Dewatering

Wellpoint dewatering and settlement tank systems manage groundwater ingress during excavation.

Water Recycling

Closed-loop treatment enables 80-95% water reuse, minimising tanker transport rates.

Mobile Plants

Containerised and trailer-mounted systems for rapid deployment and relocation between sites.

Design Parameters

TBM Slurry Flow200 – 2,000 m³/h (EPB shield dependent)
Solids Loading10 – 40% by weight (spoilt slurry)
Particle Size0.001 – 100 mm (sand to boulder fragments)
Dewatering Well Flow5 – 50 m³/h per wellpoint
Groundwater TreatmentpH adjustment, iron/manganese removal
Water Reuse80 – 95% recycling for TBM and grout mixing
FootprintCompact skids for 500 m² site compounds
MobilityTrailer/container mounted for rapid relocation

Construction Compliance

Discharge Consent

Site dewatering discharge meets local authority consent for suspended solids and pH.

Environmental Permit

Groundwater treatment complies with Construction Environmental Management Plans (CEMP).

Waste Hierarchy

Dewatered spoil meets landfill acceptance criteria or is recycled as engineered fill.

Project Delivery Capability

Rapid Mobilisation

Equipment dispatched within 48 hours of order confirmation. Site-ready skids minimise civil works and installation time.

Temporary & Permanent

Systems available for short-term hire during construction, or permanent purchase for long-term water management.

24/7 Site Support

Dedicated project engineers assigned to major infrastructure contracts with direct mobile contact and rapid response.

Contractor Compliance

CIS, CHAS, and Constructionline accredited. RAMS prepared for every installation and commissioning activity.

Need help with water reuse on site?

Our experts can design a system tailored to your specific requirements.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.